Boiler.



P. CRWSTI.

BOILER.

APPLICATION FILED APR. 5. 1915.

1 ,250,979 Patented Dec. 25, 1917.

Inventor:

yw-w g m Attorney.

UNITED STAT PIERO CROSTI, 0F MILAN, ITALY.

BQILER.

Application filed April 5, 1915.

To all whom it may concern:

Be it known that I, Prnno CRos'rI, a subject of the King of Italy, resident of Milan, in the Kingdom of Italy, No. 12 Via Pietro Verri, have invented new and useful Improvements in Boilers, of which the following is a specification.

My former patent applied for October 20th, 1918 Serial No. 796,254 discloses a single fire-box to which several boiler shells are connected, the crown sheet of the fire box being constituted by a plate into which the top ends of one or more bundles of pendant water tubes are fitted whose lower ends are inserted in one or more semi-cylindrical drums.

The present invention relates to an improved boiler presenting several advantages over the said former arrangement, such as in respect to the pendant arrangement of the drum and water tubes Within the fire box, greater strength of the plate forming the crown sheet of the fire box, greater resistance to shocks, less liability to the formation of soot deposits, and dispensing with the crown sheet reinforcing stay-rods, while on the other hand it enables an easy connection of the fire box crown sheet to the boiler shell preventing the relative displacements of these parts, and finally allows of the free expansion of the fire box top plate without setting up stresses against the fire tube plates.

The annexed drawings show one form of carrying out the invention in which: Figure 1 is a longitudinal section through the center line of a fire box to which two boiler shells are connected; Fig. 2 is a cross section through A-A in Fig. 1, and Fig. 3 .is a cross section through BB in Fig. 1.

In the fire box common to several boiler shells the metal crown sheet a is shaped as a cylindrical or otherwise curved surface and serves as tube-plate for the top ends of one or more converging bundles of water tubes ?2 and -c-, which extend radially therefrom and whose lower ends are inserted into one Or more metallic drums (Z of circular cross section freely suspended, in the fire box, by the water tubes -b and -c, which arrangement permits of the free expansion of the said tubes and thus avoids setting up stresses.

The water tubes b may also be tapered.

The water tube 0- of larger diameter than water tubes b, constitutes the man- Speciflcation of Letters Patent.

Patented Dec. 25, 1917.

Serial No. 19,356.

hole and extends past the crown sheet a-, v

as shown on the drawings, to the outer casing --e to which it is secured. In the extension of tube c lying between the top plate zr and the outer casing e manhole openings fare provided.

The portions ---gof crown sheet a in which no water tubes b are inserted may be either plain or corrugated, or (as shown on the drawings) may be provided with one or more slots or openings -hwhich, to insure security, elasticity and greater strength of the crown sheet portions -g, are closed b means of metal caps 4J- of n shape or some other similar cross section.

The water legs on either side of the furnace may be reinforced by means of stay.

bolts as is usual in boilers of the kind referred to, but no stay bolts need be provided between the curved crown sheet a and the outer casing c.

Having described my invention, what I claim is:

1. In a steam boiler having a double wall portion surrounding the fire box, the c0mbination of a substantially cylindrical fire box crown sheet, a cylindrical water drum in the fire box coaxial with said crown sheet and having a portion of its surface substantially parallel to the surface of the crown sheet, and a plurality of rows of water tubes extending radially between said parallel surfaces and rigidly connecting them together, whereby the drum is freely suspended in the fire box.

2. In a steam boiler having a double wall portion surrounding the fire box, the combination of a substantially cylindrical fire box crown sheet, a cylindrical water drum in the fire box coaxial with said crown sheet and having a portion of its surface substantially parallel to the surface of the crown sheet, a plurality of rows of water tubes extending radially between said parallel surfaces and rigidly connecting them together, whereby the drum is freely suspended in'the fire box, one of the said tubes being of larger diameter than the others and extending to the outer casing of the double wall portion to form a manhole, and manholes in the sides of the said larger tube.

3. In a steam boiler, the combination of a pair of boiler shells arranged in alinement, a single fire box common to both shells, a double wall portion connecting the two shells and surrounding the fire box, said double wall portion comprising an outer casing and a substantially cylindrical curved fire box crown sheet, a cylindrical Water drum in the fire box coaxial with said crown sheet, a plurality of rows of Water tubes extending radially from said crown sheet and rigidly connecting thesaid crown sheet with the upper portion of said water drum, one of the said water tubes being of larger diameter than the others and extending to the outer casing to form a manhole, and manholes in the sides of said larger Water tube.

4. In a steam boiler having a double wall portion surrounding the fire box, the combination of a cylindrical crown sheet forming part of the inner wall of said double and rigidly connected with the edge thereof.

In testimony whereof I hereunto affix my signature in the presence of two witnesses. PIERO CROSTI. lVitnesses:

B. CARLO SALvoLr, LYLE Bonn. 

